Kinetics and Mechanism of the Reaction of Cl Atoms with Nitrobenzene

Smog chamber/FTIR techniques were used to study the kinetics and mechanism of the reaction of Cl atoms with nitrobenzene (C6H5NO2) in 10−700 Torr of N2, or air, at 296 K. The reaction proceeds with a rate constant k(Cl + C6H5NO2) = (9.3 ± 1.9) × 10-13 cm3 molecule-1 s-1 to give C6H5Cl and NO2 products in essentially 100% yield. The observed product yields suggest that the reaction proceeds via a displacement mechanism (probably addition followed by elimination). The UV−visible absorption spectrum of C6H5NO2 was measured. Photolysis of C6H5NO2 is estimated to occur at a rate of (3 ± 2) × 10-5 s-1 for a solar zenith angle of 25° (representative of a typical summer day at 40°N) and is likely to be the dominant atmospheric loss mechanism for C6H5NO2.